registering problem

some of guests sent me a few mails that they can't register on my forum. they said that when they enter their e-mail adress, it says it is used by another member of the forum. and when they try it again, it says the same... this is not the only problem that i have with registering. sometimes the new users don't get the activation key... so i must activate them by myself and send them the mails that they are activated, but that's quite boring. can someone tell me what is the problem?

ask them to send the email they are using and run it through a search.

user/groups then search members email. just to see if anything comes up.
also be sure to check all user options in the same place user/groups then user options

be sure to have (New accounts activation) set to user.unless you want to activate them?

then have (Send notify email on new user registrations ) set to none or admin.
yea actually have it set to admin for now. this way when someone registers you will be sent an email saying you have a new registered member.
and have (Allow new members) set to yes. then click save.

also wile your there check off any other options you want to allow or disallow and click save

then check you users inactive list again just to see if you missed anyone b/f

this should do it. if not then come back here and staff,members or myself will try to figure it out further.

hope that helps. thanks